Two-compartment hot water tank



May 13, 1958 s. N. coATEs TWO-COMPARTMENT HOT WATER TANK' Filed July 17.1957 I/IAf/I 74 74 2 INVENTOR. Kym/5y M 004 TF6 qgwm nite

TWO-COMPARTMENT HOT -WATER TANK Sydney N. Coates, Seattle, Wash.

Application July 17, 1957, Serial No. 672,499

3 Claims. (Cl. 219-38) States Patent compartment will deliver what maybe termed warm water, especially as comparedwith the water deliveredfrom the upper compartment which may be termed hot Water. Thus the useris enabled to draw off warm water, of say 148 B, when he wishes; orif"he -nee ds hotter water there is instantly available to him-anappreciable supply of hot water, at say 180 F.

It is an object to form a tank of this nature in a simple manner but ina manner in which the thermal losses are slight, and especially in thatthe warm water is the source forthe supply of hot water, whereas thecold water inlet from the main is admitted only to'the warm watercompartment of the tank and is therewarmed to the warm watertemperature, ,before it can enter the hot water compartment.

It is a further object to accomplish the ends above in a constructionwhich is entirely practical, which is well adapted to the employment ofsimple rod type immersion electric heaters, and which is readily adaptedto the replacement of such heaters whenever that is necessary.

With such objects in mind, and others as will appear more fullyhereinafter, the present invention comprises the two-compartment hotwater tank illustrated in a typical form in the accompanying drawings,as will be described more fully hereinafter, and the novel featureswhereof will be set forth in the appended claims.

Figure l is an axial sectional view through the tank of this inventionin somewhat diagrammatic form, and Figures 2, 3 and 4 are transversesections through the same at the respective lines 22, 3-3 and 44 ofFigure l.

The upright tank 1 is interiorly divided by a transverse partition lilinto an upper hot water compartment H and a lower warm water compartmentW. These two compartments are in restricted communication with oneanother through the medium of a series of holes 11, but these holes arein a particular location and of relatively small total area, as willappear hereinafter.

Within eachcompartment is a segregated heating chamber 2 or 20, the twobeing alike but differently numbered in order to distinguish readilybetween the chamber 2, which is in the hot water compartment H, and thechamber 2b in the lower warm water compartment W. These heating chambersare conveniently of U-shape in cross section and may be of uniformdiameter from top to bottom. If preferred, or if it is found necessaryto retain the rising water in these chambers longer in contact with theheating elements, they may be somewhat restricted at their upper end.The chambers 2 and 20 are located in vertical alignment with each otherand with the holes 11. Each heating chamber is open at itstop and bottomto the space within its compartment, for free circulation therein.

The hot water delivery connection 3 leads from the top of the chamber Hin alignment with the open upper end of the heating compartment 2, andthe warm water delivery connection 30 likewise leads from the spacewithin its compartment W that is directly above the open upper end ofthe heating chamber 20. Thus each delivery connection is from theportion of the compartment with which it is connected wherein the wateris most highly heated, and which receives freshly heated water as itrises from the enclosed heating chamber.

The'water is heated in each instance by suitable electric immersion typeheaters. Thus the heating elements 4 for the hot water compartment arerepresented as straight rod type heaters in U-shape'received within theheating chamber-2 and entering through an aperture in the side of thetank; and the heating elements 4% for the warm water compartment are oflike nature, similarly received within the heating chamber 21 and they,too, enter through an opening provided in the side of the tank. Each ofthese heating elements, it will be observed, is straight and readilywithdrawn or entered into the compartment by direct lateral movement,upon removal of the cover 4.1 from over its terminal ends. The heatingelements '49 and 4'are aligned vertically so that in case of need waterheated to the temperature of the warm water, for instance, in theheating chamber 20 can rise directly through the holes 11 into'theheating compartment 2, and may there be quickly raised by the heatingelement 4 to the further temperature necessarytoproduce the hot'waterfor delivery at 3.

The cold water inlet is represented at 5. Cold water is delivered onlyto the lower compartment W, at a point laterally far removed from theheating chamber 20, and at a level well below the upper end of thatheating cham ber but yet appreciably above the bottom of the same. It istherefore necessary for the cold water entering at 5 to sink to thelevel of the bottom of the compartment 20 before it may enter the same,and in doing so it must displace or mingle with the warmed water withinthe bottom of the chamber W. There thus can be no immediate and abruptcooling down of the water within the compartment W; and since the onlywater that enters the upper compartment H is that which enters throughthe holes 11 directly from the hottest water in the lower compartment W,the water in the compartment it will always be at least of thetemperature of the hottest water in the compartment W, and by propersetting of thermostatic controls the water in the compartment H willalways be actually at an appreciably higher temperature than the waterinthe compartment W. A thermostat in the compartment H is arranged inknown manner to control the heating elements 4, and the secondthermostat 45 in the chamber W is arranged in the same manner to controlthe heating elements 4d. I

T 0 complete the description of the tank, a drain connection isshown at6, with a drain valve oil; and in order to bypass any sediment that mayhave collected within the bottom of the tank and so provide an assuredoutlet for a safety valve 61, a bypass from the safety valve, connectedabove the bottom of the tank, is shown at 62, connecting for dischargepast the drain valve 69.

Insulation as indicated at 7 may be provided about the tank 1, and hasbeen illustrated but fragmentarily.

Considering first the lower compartment W, the cold water entering at 5will gradually sink to the bottom of this compartment and then will risewithin the heating chamber 20 as water previously within that chamberrises after being heated, to the upper part of the compartment.

This water, warmed to the temperature permitted by the thermostat 45,can be drawn oil at 30 for use. Some of it can rise through the holes11, but only a limited part due to the small area of such holes, andduring static conditions the water within the compartment W willcirculate within that compartment only until such time as is required toattain the required temperature, or to supply heat lost by withdrawal ofwater from the tank and the entrance of more cold water which requiresheating.

If hot water is desired to be withdrawn at 3, then this requiresreplacement of the withdrawn water, and the replacement comes throughthe holes 11 from the hottest water in the compartment W. If, indeed,withdrawal at 3 is long continued, the water which enters thecompartment H through the holes 11 is that which has just risen from theheating elements 40 in the lower compartment, and this water atapproximately 140 is delivered directly to the heating elements 4, andis by them heated to the higher temperature, and by the time it rises tothe top of the heating chamber 2 it is at proper temperature ready fordelivery at 3. During static conditions, however, any loss of heat fromthe hot water will merely cause circulation within the compartment Huntil substantially the entire contents of the compartment H have beenheated to the maximum temperature. While conditions are static, there isno entry of cold water at 5 to the tank as a whole, and circulationcontinues within each of the compartments separately until the Water ineach has risen to the desired temperature for that compartment, andthereafter circulation within that compartment ceases, although notnecessarily within the other compartment. The result is that there isconstantly available a supply of warm water and a supply of hot water;and if there is a long-continued demand for hot water, the dual actionjust described will, with a high degree of reliability, supply thedesired amounts of properly heated hot water.

I claim as my invention:

1. A hot water heater comprising an upright tank, a transverse partitionintermediate its ends dividing the tank into upper and lowercompartments, said partition having a group of apertures for limitedcommunication between the two compartments, a heating chamber in eachcompartment, freely open at top and at bottom to the space therein, andeach aligned with said group of apertures, whereby heated water risingfrom the lower 8. heating chamber will in part rise through theapertures to enter the upper heating chamber, and in part will circulatewithin the lower compartment, and heated water rising from the upperchamber will circulate within the upper compartment, a cold water inletadmitting to the lower compartment only, two hot water deliveryconnections, from the upper portion of the respective compartments, aheating element in each chamber acting upon the water risingtherethrough, and thermostatic control means for the respective heatingelements, to maintain the water in the upper compartment at a giventemperature, and that in the lower compartment at a given lowertemperature.

' 2. A hot water heater as in claim 1, wherein the hot water deliveryconnection from the upper compartment is located in vertical alignmentwith the upper end of the upper heating chamber.

3. A hot water heater as in claim 1, wherein the cold water inlet islocated in the lower compartment laterally distant from the heatingchamber therein, and at a level intermediate the top and bottom of saidheating chamber.

References Cited in the file of this patent UNITED STATES PATENTS1,047,389 Cooper Dec. 17, 1912 2,012,101 Hynes Aug. 20, 1935 2,375,871Reifenberg May 15, 1945 2,380,545 Pankow July 31, 1945 2,411,675Alexander Nov. 26, 1946 2,712,052 Buhne June 28, 1955

